Question

1. Define membrane potential. 2. Describe how membrane potential is established. What physical feature of the plasma membrane is essential for the establishment of membrane potential? 3. Describe how membrane potential is maintained. 4. Write a number that represents resting membrane potential. 5. If a gated sodium ion channel is opened, membrane potential is changed. Tell the direction of the change. 6. If a gated potassium ion channel is opened, membrane potential is changed. Tell the direction of the change.

Answer 1

QUESTION 1

The role of membrane potential is very much important in not only the functioning of the cell but also to provide the signals to the cell which results in the entire body functioning. It is basically the differences that occur in the membranes of the cell matrix, when a cell is in a unactivated or resting phase

It is the properties of  electric and chemical which are related to the membranes of the cells and the ions and in which method does these forces result in the determination of the gradients caused in the electrochemical methods.

QUESTION 2

So in order to understand the viability of the cell it is the membrane potential of the cell membranes that is to be studied. The ions like key role of K⁺ and   H+, Na⁺,Cl⁺ through the cell membranes result in the electrical potential gradients. The transduction of the signals, photosynthesis, transportation of the nutrients and ions through the membrnes of the cell, stimuli of the cell externally are all result of the membrane potential.

The method of depolarization which is called the decrease of the potential in transmembranes and the Hyperpolarization which is the raise in the potential difference througth the membranes are the key aspects of membrane potential.

QUESTION 3

As already mentioned in the above answers the membrane potential is because of the differences that are caused within thecell and outside the cell. This is basically the difference of number of ions of potassium that are positively charged within the cell and external to the cell is the resting menmbrane potential

During the inactive or the resting phase of the cell or the membrane of the cell, the accumulation of the potassium ions within the cell occurs because of the concentration gradient.

This entire process of the sodium and the potassium potential gradient results in the establishing the potential of the membrane.

The pumping of potassium and the sodium lets in two of the potassium ions simultaneously removing three of the sodium ions at the rate of One ATP consumed. More the number of cations oozed out higher is the negative charge with respect to the extracellular fluid. The cytoplasm has proteins which are negatively charged that are responsible for sending out the Chloride ions .

QUESTION 4

The differences in the varied concentration within and external to the cell is referred to as the  resting membrane potential. As mentioned above the gradient of the positively charged ions within and outside the cell results a value of -30mV to -90mV of the membrane potential that is in resting phase.

The resting membrane value varies with different types of cells. I have mentioned them in the table below:

CELL TYPE	VALUE OF RESTING MEMBRANE POTENTIAL
NEURON	-65mV ( milli volts)
CELLS OF CARDIAC MUSCLE	-80mV
CELLS OF SMOOTH MUSCLE	-55mV
CELLS OF SKELETAL MUSCLE	-90 mV

QUESTION 5

If we take tahe Sodium ions which is the ion that crosses the membrane,It is to be noted that the concentration of sodium ions is much greater outside the cell thean within the cell., because of which the movement happens down the concentration gradient which is entering of ions into the cell. In a total this is the reason for the positive charge of the within the cell

And this results in maintaing the membrane potential to be positive in cells where the sodium equilibrium potential is establshed.

QUESTION 6

So when the Potassium ions make their movement acroos the cell membrane this results in the membrane potential of a resting neuron.

.In the process of the opening of the potassium channels the ions move outside the cell inorder to maintain the concentration gradient. When this happens the cell loosed the positive chrge every single time a potassium ion leave the cell to outside. This causes the positive chrge outside the cell environment and a negative charge inside the cell environment. This ultimately is the reason for the establisment of the electrical potential through the cell membrane

I hope this helps. Please do let me know if I can help you with anything.

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